INFLUENCE OF ASPIRIN IN THE MANAGEMENT OF ASYMPTOMATIC CAROTID-ARTERY STENOSIS

Purpose: Aspirin therapy is recommended commonly for symptomatic extracranial carotid artery occlusive disease. However, its role in the management of asymptomatic carotid artery stenosis has not been reported previously. Methods: In 11 clinical centers during the period 1983 to 1991, 444 adult male patients with significant asymptomatic carotid artery stenosis (greater-than-or-equal-to 50% arteriographically) were randomized to receive optimal medical management including aspirin plus carotid endarterectomy (n = 211) or optimal medical management alone (n = 233). At the conclusion of the study (mean follow-up time 47.9 months), at the time of a patient's death, or at occurrence of a neurologic end point, 16% of patients (n = 72) were not taking any aspirin, 51% (n = 226) had been converted to receiving enteric-coated aspirin, and only 33% (n = 146) were taking plain aspirin (27% at reduced dosage). Among patients from the medical group, 37 (16%) of 233 were not taking any aspirin and formed the basis for this retrospective analysis of the group for which no control population was available. Results: Mortality rates in this group were not significantly different for patients not taking aspirin as compared with the rates for those taking aspirin, although patients not taking aspirin had a higher incidence of myocardial infarction (27%) as compared with patients taking aspirin (8%), p < 0.05. The incidence of ipsilateral neurologic events for patients not taking aspirin as compared with that for patients who were taking aspirin, respectively, was as follows: stroke, 13.5% and 8.7%,p > 0.05; stroke and transient ischemic attack, 37.8% and 17.3%, p < 0.05. No significant differences were observed in stroke severity scores for patients taking or not taking aspirin. Conclusion: These data suggest that patients with significant asymptomatic carotid artery stenosis who are intolerant of aspirin have a higher incidence of neurologic events than those patients able to tolerate the drug.